<?php
if( isset( $_GET['act']  ) ) {
    $act = $_GET['act'];
    if( $act == 'add' ) {
        // echo "Them";
    } elseif ( $act == 'edit' ) {
        // echo "sủa";
    } elseif ( $act == 'delete' ) {
        # code...
    }
}
?>